Ratcatcher
by Emmeebee
Summary: AU oneshot set at the end of the Prisoner of Azkaban. Cat!Minerva is, as per the Headmaster's orders, on guard duty for Sirius Black when she finds a curious little nine-toed rat that she can't help but play with.


She had told Albus that the mission would be futile, but he had insisted – and no one refused when the Headmaster insisted. Still, no one with half a brain would try to get to Potter again, and Black was nothing if not brilliant; he might be single-mindedly fixated on killing his godson, but even his Azkaban-twisted mind wouldn't tell him it was a good idea to try again so soon after being seen.

Despite her best efforts to steel herself against it, it pained her to think about the Black boy rotting away half-mad in that hellhole. The charisma, supposed fierce loyalty and laissez-faire attitude that had tricked them all had also endeared him to them, and she couldn't help but shiver at the image of that frustrating, mischievous, _good _student trapped there. It was still hard to reconcile the image of his teenage self with that of the traitor he became – she preferred to avoid thinking about what it was that changed him, whether it was something she'd done or failed to notice.

The sound of distant shouts coming from the Forbidden Forest jolted her out of her reverie. She let out a soft hiss at the thought of the centaurs partaking in whichever moonlit festival it was this time. The Forest was the only place that they could be properly monitored by someone who stood a chance of reprimanding them, but she didn't like it. She knew Albus didn't either. The only reason he didn't rally the teachers up to massacre them when they initially moved in was because he knew that some would escape and would likely terrorise the closest non-magical village for vengeance, and they were willing to make a treaty with him. If they ever got to one of the girls… well, she'd seen Albus unleash his fury the last time that had happened, wiping out the fifteen centaurs that had been involved. The only good thing about the centaurs was that they each knew that anyone who harmed a human would be signing their death warrant as they did it.

As the shouts faded away – good, they must have been moving further into the forest – she noticed the sound of a soft rustling through the grass. Looking down from her perch on the lowest hanging branch of the tree closest to Hogwarts' gates, she saw a large grey rat scurrying through the damp grass. Instinctively, she leaped down and pounced on it in one fluid motion before starting to batter it between her paws. A few moments later, the realisation of exactly how utterly uncharacteristic of her that was hit her. She had always been good at managing her cat instincts, but for some reason the urge to play with – she casually lifted it up by its tail to check its sex – him had overwhelmed her. She fixed her unblinking yellow eyes on the frightened creature as it twisted and turned and tried to escape her. Curiously, it seemed to struggle even more once it saw her face, almost as if it had seen her before. That was crazy; she hadn't been out in this form in weeks and certainly hadn't given it any reason to fear her prior to tonight. Still unsettled, she lifted her empty paw and poked it, receiving a terrified squeak in response. She considered letting it go and returning to her watch, but her gut compelled her to stay. Her instincts had served her well over the years, even if they'd been wrong about Black, and they were usually heightened in her Animagus form. Deciding to focus on the matter later, she slipped behind the tree so that she would be out of side of the entrance and, still clutching the squirming thing, returned to human form, hurriedly Stunning it as it tried to twist around to bite her.

"_Transformus_," she thought, picturing a sealable box with airholes as she pointed her wand at a leaf. When it had been transfigured, she slipped the rat into it before securing it carefully. She didn't want it to slip out and try to bite her again. Barely moments after she had put the box in one of her deep cloak pockets, she transformed once again, lightly and quickly scampering up the tree to resume her overnight vigil.

-r-

A flash of silver juxtaposed against the dark sky was coming at her from the corner of her gaze. Turning her head slightly so as not to alert anything to her awareness, she observed it without blinking until long after she'd recognised shimmering phoenix. The silver bird stopped in front of her and when its mouth opened the Headmaster's voice echoed softly around her corner of the grounds. "Minerva, there was an incident in the Shrieking Shack. Mr Potter, Miss Granger and Mr Weasley are in the hospital wing. Your target has been apprehended. He is on the third floor in the room next to the statue of Sir Arridius. I will be outside. Please come at once."

She sprinted across the silent grounds, only returning to human form for the brief period of time that it took to open the large oak castle doors.

-r-

Albus was observing the statue with a curious expression on his face when she arrived. "Good evening, Minerva. I trust your vigil was not unpleasant."

She ignored his pleasantries, merely casting a series of anti-eavesdropping charms before questioning him. "What's going on, Albus? How are my students? Why were they in the shack? And why on earth do they have to always get themselves into these messes?"

"They are fine. Mr Potter is rather shaken after another close encounter with the Dementors, but he managed to fight them off. Curious, given the fact that Remus didn't seem to think he'd mastered it enough yet, but impressive. Other than a few scrapes and bruises, the only real injury is Mr Weasley's broken leg, and Poppy will have that fixed in no time. They went to visit Hagrid before Buckbeak's execution and a large black dog dragged Mr Weasley into the shack when they were heading back to the castle. His friends, naturally, went after them. The dog was Sirius Black, Minerva. He, James Potter and Peter Pettigrew became unregistered Animagi in their fifth year in order to keep Remus Lupin company every full moon."

She took a quick breath but didn't interrupt.

"Remus Lupin met them there, I presume when he was locking himself in for the night. Somehow Severus ended up there too. Black explained… It seems that we were mistaken, Minerva," Albus said, sighing tiredly. "It was Peter Pettigrew, not Sirius Black, who was the Potter's Secret Keeper in the end."

"What – no – that doesn't make sense, Albus. They made Black the Secret Keeper. He was the obvious choice. Why would they have changed it?"

"He was the obvious choice," Albus repeated. "From what Black said, he was aware that anybody who knew of the Charm would know James had chosen him, so they changed it to Peter, who then went into hiding… James became his Secret Keeper and he became the Potters'. Black planned to maintain his involvement with the Order while leading the Death Eaters on a merry chase around the country."

"Are you sure, Albus?"

"Without a doubt."

The sombre lady considered it for a millisecond before nodding. "That's why Black went after Pettigrew; it makes sense. But how are we to prove it? Black killed Pettigrew. It's his word against twelve years of conviction in his guilt…"

"Pettigrew is alive. It was why Black was trying to get into the castle. Pettigrew was masquerading as Ronald Weasley's pet rat Scabbers, previously owned by Percy Weasley."

"He's been in the castle _all this time_? In _Gryffindor Tower_?"

"So it would seem."

"Is Pettigrew under custody?"

"Remus forgot the day in the midst of all the excitement. Pettigrew escaped when Remus turned. The Minister is on his way. Severus informed him of Sirius' presence."

They both stared at the statue, both well aware that when Fudge arrived Sirius Black would be returned to Azkaban faster than anyone could even start to say, 'objection'.

A rattle in Minerva's pocket drew her attention. Frowning, she reached inside it and felt a cool wooden surface. Suddenly, she remembered the outcome of her vigil, seeing it in a new light with the recent information. "Albus, what did you say Pettigrew turns into?"

"A rat. Sirius changes into a dog and James became a stag."

She pulled out the box and handed it to him. "I came across this when I was outside and felt that there was something off about him."

"Is this…?"

"A rat, yes. It might not be him, but, as I said, I felt like something was wrong."

Albus cast a charm so that the box was transparent. Seeing the wizard staring down at him, the rat went into a frenzy, charging at the walls and scratching them with its nine little claws.

"It has nine toes," Albus commented lightly.

"All that they found of Pettigrew was a toe."

"Yes." Albus opened the door to the room-turned-cell, wandlessly removing Minerva's protective charms as he did so. "Sirius, would you accompany me to the hospital wing? Minerva appears to have found Peter. I don't see why we shouldn't await the Minister in the hospital wing with Mr Potter and his friends."

"Are you sure it's him?" was said in a firm voice. Minerva frowned when the once-imprisoned wizard came into view. His appearance was sallow, his long hair hanging in a mess around his face and a haunted, exhausted look in his eyes. He was as different an image from the energetic youth she'd known as she could imagine.

_At least, however, he is alive and will one day be well again. _"It is good to see you alive, Sirius. I am sorry for doubting you."

"We were in a war; if someone looked guilty, you had to assume they might be. And I didn't exactly make myself look innocent when I was apprehended."

"That does not change the fact that betrayal and bloodism were never in your repertoire."

Sirius smiled grimly. "I didn't think they were in Wormtail's, either." He glanced at the box. "That's him, alright. I'd recognise him anywhere."

"Yes, and we're going to be having a long talk about that when this is cleared up," Minerva said stiffly. "It was extremely irresponsible of you…"

She didn't stop lecturing Sirius until they had reached the doors of the hospital wing. "I'm feeling more back to normal by the minute," he said dryly, before a slow grin spread over his face. Minerva felt a sense of foreboding much like the one she always did whenever she'd heard that Potter and his friends had found their way into more danger. "Minnie, I just realised... you were a _cat _when you caught him, weren't you? And you wouldn't have known who he was. Does the Headmaster need to talk to you about not playing with your food?"

"I had a hunch of sorts," Minerva said primly, turning and striding into the hospital wing before he could make any further comments. Unfortunately, the closing doors did nothing to hide his barking laughter at the image of her chasing rats and birds and other woodland animals. Despite her irritation at his jibe, it was good to hear him laugh so freely again. Hopefully it would be at someone else next time, however. Perhaps she should inform him that neither Harry nor Hermione had much experience with people making jokes at their expense and could do with someone to teach them to laugh at some of the things people said about them.

"Mr Black," Albus said quietly once the doors had closed. "You may speak with Harry briefly, but I have a task for him and Miss Granger to do after we catch him up. An innocent creature was to be executed this evening and I rather think that I'd like to irritate Lucius Malfoy by having it inexplicably go free."

Sirius nodded. "Anything to annoy that git."

"Indeed. Shall we inform your godson, then?"

Sirius was barely through the doors of the hospital wing when he was tackled by an enthusiastic and relieved Boy Who Lived. "_Oof_. Harry–"

"You're alright, McGonagall said Dumbledore has the rat, you're not going back there, you're not going back there…"

Sirius kissed the top of the boy's head as he wrapped his arms around him. "The offer's still open, you know. You could… you could come to look at some of the family property with me, find somewhere you'd be comfortable visiting… or staying. Or we could sell one of them and find somewhere else. It might take a while to refurbish and ward wherever you choose, and everywhere else so that no one can tell which we're in, but… but we can."

"Anywhere. _Anywhere_."

Minerva watched on with a bittersweet smile as Sirius patted Harry's back before stepping back and walking towards Harry's friends' beds. Although tears still dripped from his eyes, her adventure-prone – and, she admitted to herself, second favourite – Gryffindor looked happier than she'd ever since him before as he passed by his own bed and sat with Sirius and Hermione next to the bed where Ron, still unconscious as the potions did their work on his leg, lay.

"Minerva," Albus eventually said. "The wards say that the Minister has arrived. Would you bring him up here? I have some matters to discuss with Mr Potter and Miss Granger. Er, perhaps you should take a scenic route on your way back. And tell him that I demand for all Dementors to be off school grounds before he sets foot in the castle. They are no longer needed." He winked at an uncomfortable-looking Hermione. "Phrase it a little more politically, perhaps."

* * *

><p>AN I was going to upload this last night but got caught up in the hubbub of Christmas Eve and visitors. So, Merry Christmas! If you don't celebrate it, I hope you still had a great, safe day. Mine was a bit tumultuous at times - getting up so early didn't help - but altogether fairly good. A kid from church who I haven't seen for a while now looks like a miniature Merry Brandybuck, which was adorable. This oneshot is basically a bit of wish fulfillment for how I wish POA had ended.


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